"Pneumatic tyres on mobile equipment are dangerous pressure vessels"

The recent and unfortunate death of a wheel fitter in New South Wales, Australia, as a result of the explosion of a container handling reach stacker, five-piece split rim wheel assembly, has highlighted the dangers of using pneumatic tyres on mobile equipment.

It’s not the first time that an accident of this nature has occurred. At MLA Holdings, big trucks with a lifting capacity of 16,000 kg are usually equipped with multipiece rims and pneumatic tyres. According to safety regulations, the tyre must be fully deflated when a wheel is being removed from a heavy truck or container handler. The reason for this is that, when removing a tyre that is full of air pressure, you run the risk of a catastrophic wheel explosion, the tyre or rim can be cracked or damaged, which, in turn, will then explode due to the high air pressure (up to 1100 kPa or 155 psi) within. Ignoring precautions could pose a serious safety risk for technicians and tyre fitters working on these trucks.

These explosions can have devastating consequences. MLA’s National Engineering Manager, Gary Cassel has worked in the industry for 48 years and knows a safety hazard when he sees one. He states:

“In the mobile equipment maintenance field, it is of prime importance for frontline people to be able to identify the hazards associated with the task that they are about to undertake and be capable and vigilant about implementing measures to mitigate the risks of the associated hazards to ensure their safety and the safety of others.”

In an attempt to counteract this increasing and extremely dangerous problem, MLA Holdings uses a wheel and tyre safety supplement to instruct tyre fitters and technicians on how to safely and correctly remove and replace tyres.

Here are a few instructions on how to safely remove and replace wheels:

Removal

1. Park the truck on level ground in a safe working area.
2. Chock the wheels.
3. Isolate the ignition and batteries.
4. Jack up the truck at the jack points and secure with an axle support device (do not rely on just the jack).
5. Before removing any wheel nuts, fully deflate all wheels that are to be removed.
6. Remove the wheel nuts and use a suitable lifting device to remove the wheel.

Replacement

1. Inspect the tyre and rim for damage and cracking, reject if faulty.
2. Place wheel into tyre safety cage and inflate to recommended inflation pressure, inspect wheel for defects then fully deflate the tyre, remove from tyre safety cage and rectify any defects found.
3. Use a suitable lifting device to place the wheel onto the truck and tighten wheel nuts, in correct sequence, to recommended torque setting.
4. Place a protection device near the wheel assembly to minimise the trajectory zone.
5. Inflate the tyre to the recommended inflation pressure from outside the trajectory zone.
6. Inspect the wheel for defects, reject if faulty.
7. Remove the protection device, axle support device and jack.
8. Test run truck and retighten wheel nuts in correct sequence to recommended torque setting.
9. Return the truck to service.
10. After 10 hours of use, retighten wheel nuts, in correct sequence, to recommended torque setting.

MLA believes the implementation of these safety instructions is paramount to prevent death and injury caused by wheel explosion. While this safety instruction provides a positive solution to the problem, it will not fix it unless technicians and wheel fitters recognise the hazards and are vigilant when working on heavy trucks and container handlers. Taking the necessary precautions and dropping the ‘it won’t happen to me attitude’ can often make the difference between life and death.

Pneumatic tyre explosions are not a new issue; however, the problem has intensified recently. It’s believed that the reason behind this is education. More safety manuals, awareness, education and vigilance are the key to combating this very serious issue.